Doctors should prescribe exercise to all type 2 diabetes patients who are healthy enough to work out, states an editorial published with the study in the Annals of Internal Medicine.

(If you are living with type 2 diabetes, do you exercise regularly? Talk about it on WebMD's Diabetes Type 2 Support Group message board.)

Exercise and Diabetes

The new Canadian study on exercise and diabetes included 251 adults with type 2 diabetes.

On average, they were in their early 50s(age range: 39-70) with an obese BMI (body mass index) of 35. None was taking insulin and none was an exerciser.

First, the patients got checkups. That's always a wise thing to do before starting an exercise program, even for people who don't have diabetes.

Having been medically approved for the study, all patients got a modest amount of supervised exercise for a month, just to make sure they could stick with an exercise plan.

After that first month, the researchers split participants into four groups:

Aerobic exercise only

Resistance training only

Aerobic exercise and resistance training

No assigned exercise

Diabetes Workouts

The exercise groups worked out three times per week at a gym (with their expenses paid by the researchers).

For aerobic exercise, participants used a stationary bike or treadmill, gradually lengthening their workouts from 15 minutes to 45 minutes. For resistance training, they performed seven exercises using weight machines, eventually doing two to three sets of each exercise.

Patients assigned to aerobic exercise and weight training did the full aerobic workout and the full resistance training workout, three times per week.

The researchers -- who included the University of Calgary's Ronald Sigal, MD, MPH -- didn't ask the participants to try to lose weight or to diet.

Reaping the Benefits

Participants followed their assigned workouts for 22 weeks.

All three exercise groups improved their blood sugar control based on their hemoglobin A1c level, which indicates blood sugar control over the previous two to three months.

People who got aerobic exercise and also lifted weights had the biggest improvement in hemoglobin A1c. Not surprisingly, not exercising yielded no improvements in hemoglobin A1c.

The bottom line: For the biggest benefit, get aerobic exercise and resistance training. If you can't manage both, at least do one or the other, as each is better than doing nothing.

If the benefits of exercise for type 2 diabetes patients could be captured in a pill, diabetes experts would be quick to prescribe that pill, states the editorial published with the study.

"Failing to prescribe exercise to patients with diabetes is simply unacceptable practice," write the editorialists, who included William Kraus, MD, of Duke University Medical Center.